<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="app">
    <div v-color="color">Hello ！</div>
    <button @click="changeColor">切换颜色</button>
</div>
</body>
<script src="../../js/vue.js"></script>
<script>
    Vue.directive('color', {
        bind: function (el, binding, vnode) {
            el.style.color = binding.value
        },
        update(el, binding) {
            el.style.color = binding.value
        }
    })
    var vm = new Vue({
        el: '#app',
        data() {
            return {
                color: 'red'
            }
        },
        methods: {
            changeColor() {
                this.color = '#' + Math.floor( Math.random() * 0xffffff ).toString(16);
            }
        }
    })
</script>
</html>
